SOLUTION: Prove that: tanx +tan(x+pi/3) +tan(x+2pi/3)=3

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Question 221254: Prove that:
tanx +tan(x+pi/3) +tan(x+2pi/3)=3
Answer by Edwin McCravy(20060) About Me  (Show Source):
You can put this solution on YOUR website!
tan%28x%29+%2Btan%28x%2Bpi%2F3%29+%2Btan%28x%2B2pi%2F3%29=3

Sorry, but that is NOT an identity.  For if 
we substitute x=0:

tan%280%29+%2Btan%280%2Bpi%2F3%29+%2Btan%280%2B2pi%2F3%29=3

tan%280%29+%2Btan%28pi%2F3%29+%2Btan%282pi%2F3%29=3

And by special angles, tan%280%29=0, tan%28pi%2F3%29=sqrt%283%29, tan%282pi%2F3%29=-sqrt%283%29

+0+%2Bsqrt%283%29+%2B%28-sqrt%283%29%29=3

0+%2B+sqrt%283%29+-+sqrt%283%29+=+3

0+=+3

This is false.  Perhaps you copied it wrong.

Edwin